what is better ? alky inj or fmic ?
11-17-2005 | 09:34 PM
#2
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Joined: Mar 2003
Posts: 2,023
From: Phoenix, AZ
Car Info: Subaru Impreza WRX 2002
This is a really interesting topic -- I hadn't considered that an alchohol injection system might be a substitute for a FMIC (producing the same effect of cooling the charge and avoiding heatsoak). Certainly even if alchohol/water injection was even 80% to 90% as effective as a FMIC, you'd still gain by keeping your "sleeper" status and avoiding the lag associated with all the extra piping...
Please, someone who's tried this on the EJ20, jump in!
Please, someone who's tried this on the EJ20, jump in!
11-19-2005 | 09:07 AM
#5
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Posts: 15,494
From: Participating in some Anarchy!
Car Info: 2005 LGT wagon
Originally Posted by lookin for sube
oaf on the boards has it but it is on an sti and he has some nice numbers ........
Water/alcohol injection can be looked at as liquid intercooling; it prevents pre ignition by raising the effective octane rating ofthe intake charge.
After installing a few FMICs, it's my opinion that h20/alcohol is the way to go.
Most front mounts are a pain to install, have multiple points to introduce vacuum/pressure leaks, and increase the induction route by ~5-6ft, decrease safety in the event of front end collision, etc.
On the positive side, they can be cheaper in the long run, add to the overall bling of a car, and if you're running a really big turbo, they out perform(flow-wise) the TMIC.
My mods:
-Injen intake.
-Gutted OE DP
-Greddy catback.
-Aquamist basic injection kit.
-Custom tuned Cobb AP
These few mods translates into 290wt/270whp up from a stock 230wt/227whp on the same dyno.
That looks like $2000 for an extra 60wt/43whp.
But, it's a safe, reliable increase, with room for more.
One thing that is simply amazing is that the torque & power bands rise quickly & stay very flat to redline.
I have driven STis that, on paper, put out more torque/power, but are slower than my car.
Why is that?
Because all of their power comes on near redline due to the larger turbo & 7 feet of intake routing!
Also, if you pop my hood, every looks compleatly stock, which here in The People's Republic of Kalifornia, will save me a hassle.
Last edited by FW Motorsports; 11-19-2005 at 09:11 AM.
11-20-2005 | 06:50 PM
#7
Thread Starter
Registered User
Joined: Jun 2005
Posts: 242
From: sactown
Car Info: 04 wrx wagon
Originally Posted by Oaf
Shhhh....don't let the cat out of the bag.
Water/alcohol injection can be looked at as liquid intercooling; it prevents pre ignition by raising the effective octane rating ofthe intake charge.
After installing a few FMICs, it's my opinion that h20/alcohol is the way to go.
Most front mounts are a pain to install, have multiple points to introduce vacuum/pressure leaks, and increase the induction route by ~5-6ft, decrease safety in the event of front end collision, etc.
On the positive side, they can be cheaper in the long run, add to the overall bling of a car, and if you're running a really big turbo, they out perform(flow-wise) the TMIC.
My mods:
-Injen intake.
-Gutted OE DP
-Greddy catback.
-Aquamist basic injection kit.
-Custom tuned Cobb AP
These few mods translates into 290wt/270whp up from a stock 230wt/227whp on the same dyno.
That looks like $2000 for an extra 60wt/43whp.
But, it's a safe, reliable increase, with room for more.
One thing that is simply amazing is that the torque & power bands rise quickly & stay very flat to redline.
I have driven STis that, on paper, put out more torque/power, but are slower than my car.
Why is that?
Because all of their power comes on near redline due to the larger turbo & 7 feet of intake routing!
Also, if you pop my hood, every looks compleatly stock, which here in The People's Republic of Kalifornia, will save me a hassle.
Water/alcohol injection can be looked at as liquid intercooling; it prevents pre ignition by raising the effective octane rating ofthe intake charge.
After installing a few FMICs, it's my opinion that h20/alcohol is the way to go.
Most front mounts are a pain to install, have multiple points to introduce vacuum/pressure leaks, and increase the induction route by ~5-6ft, decrease safety in the event of front end collision, etc.
On the positive side, they can be cheaper in the long run, add to the overall bling of a car, and if you're running a really big turbo, they out perform(flow-wise) the TMIC.
My mods:
-Injen intake.
-Gutted OE DP
-Greddy catback.
-Aquamist basic injection kit.
-Custom tuned Cobb AP
These few mods translates into 290wt/270whp up from a stock 230wt/227whp on the same dyno.
That looks like $2000 for an extra 60wt/43whp.
But, it's a safe, reliable increase, with room for more.
One thing that is simply amazing is that the torque & power bands rise quickly & stay very flat to redline.
I have driven STis that, on paper, put out more torque/power, but are slower than my car.
Why is that?
Because all of their power comes on near redline due to the larger turbo & 7 feet of intake routing!
Also, if you pop my hood, every looks compleatly stock, which here in The People's Republic of Kalifornia, will save me a hassle.
sorry oaf ! yep Im looking forward to my little 2.0 making some good numbers !!!! kinda like the little engine that could....I think I can ...I think I can .....i think I can.... thanks for chiming in and have a great turkey day!!!!
11-21-2005 | 09:22 PM
#8
VIP Member
Joined: Mar 2003
Posts: 2,023
From: Phoenix, AZ
Car Info: Subaru Impreza WRX 2002
Not to rain on the parade, but something about this bothers me. If what Oaf and the aquamist/coolmist/etc. sites are saying is true, alchohol/water injection is 40hp for $400 and everything is smiles and four-leaf clovers.
Pardon my cynicism, but there HAS to be a downside to this, or it would come on a factory car stock -- even a Ferrari, Viper or Porsche. If a little $23k Japanese sports sedan can benefit from this, why don't the $100k exotics have it (or the American muscle cars?)
I think if you used water injection as a safety cushion to tune your car into an area where it would normally experience severe detonation, and then you had some type of failure in the water/alchohol injection system (air bubble, clogged injector, ran out of water) you'd experience an engine-threatening incident. Would the Subaru ECU be quick enough to go into "limp mode" before you cracked any pistons? What about gravity or momentum sloshing the water around in the tank under hard driving or track grades?
I was reading on one forum that one of the downsides of using pure methanol was that the cooling in the combustion chamber on the intake stroke was so profound that it causes huge stress on the cylinder, valves and piston as they are repeatedly supercooled and then heated hundreds of times per second. Obviously you can try to avoid this problem by adding distilled water, but has anyone studied the long-term effects of this on an engine block?
I also think an injection system would be a total deal-breaker when it came time to sell the car; I've talked to a few co-workers about this, both tech-savvy and clueless, and they are universally freaked out by the idea of injecting water/alchohol mist into an engine during a boost cycle. A prospective buyer would see this as a sign that the car has been taken all the way to race car and probably driven to heck.
I'm not trying to be a buzzkill; I'm just curious why such a win/win mod is so rare, when it seems so logical. Would a CO2-sprayer for the intercooler have the same effect, without having to inject anything into the intake manifold?
Pardon my cynicism, but there HAS to be a downside to this, or it would come on a factory car stock -- even a Ferrari, Viper or Porsche. If a little $23k Japanese sports sedan can benefit from this, why don't the $100k exotics have it (or the American muscle cars?)
I think if you used water injection as a safety cushion to tune your car into an area where it would normally experience severe detonation, and then you had some type of failure in the water/alchohol injection system (air bubble, clogged injector, ran out of water) you'd experience an engine-threatening incident. Would the Subaru ECU be quick enough to go into "limp mode" before you cracked any pistons? What about gravity or momentum sloshing the water around in the tank under hard driving or track grades?
I was reading on one forum that one of the downsides of using pure methanol was that the cooling in the combustion chamber on the intake stroke was so profound that it causes huge stress on the cylinder, valves and piston as they are repeatedly supercooled and then heated hundreds of times per second. Obviously you can try to avoid this problem by adding distilled water, but has anyone studied the long-term effects of this on an engine block?
I also think an injection system would be a total deal-breaker when it came time to sell the car; I've talked to a few co-workers about this, both tech-savvy and clueless, and they are universally freaked out by the idea of injecting water/alchohol mist into an engine during a boost cycle. A prospective buyer would see this as a sign that the car has been taken all the way to race car and probably driven to heck.
I'm not trying to be a buzzkill; I'm just curious why such a win/win mod is so rare, when it seems so logical. Would a CO2-sprayer for the intercooler have the same effect, without having to inject anything into the intake manifold?
11-22-2005 | 02:24 PM
#9
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Joined: Sep 2004
Posts: 1,180
From: An ALMS race near you
Car Info: 03 MBP WRX
^^^Any hp adding mod decreases reliability, but a fmic does seem safer. I would think that the main reasons why alcohol injection is not available on stock cars are the lack of knowledge by the general public, the hassle of refilling the methanol tank and the risk of running out of methanol. Like you said, if the methanol runs out at wot the ecu probably isn't fast enough to switch maps. The user needs to be aware of how much methanol they have left, and they need to run EM with switchable maps.
11-25-2005 | 11:01 PM
#10
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Posts: 1,888
From: Marin - www.PachecoRanchWinery.com
Car Info: 00 BRP RS LIC'd 01 EJ207 + non DCCD 6 Speed
Originally Posted by meilers
Not to rain on the parade, but something about this bothers me. If what Oaf and the aquamist/coolmist/etc. sites are saying is true, alchohol/water injection is 40hp for $400 and everything is smiles and four-leaf clovers.
Pardon my cynicism, but there HAS to be a downside to this, or it would come on a factory car stock -- even a Ferrari, Viper or Porsche. If a little $23k Japanese sports sedan can benefit from this, why don't the $100k exotics have it (or the American muscle cars?)
I think if you used water injection as a safety cushion to tune your car into an area where it would normally experience severe detonation, and then you had some type of failure in the water/alchohol injection system (air bubble, clogged injector, ran out of water) you'd experience an engine-threatening incident. Would the Subaru ECU be quick enough to go into "limp mode" before you cracked any pistons? What about gravity or momentum sloshing the water around in the tank under hard driving or track grades?
I was reading on one forum that one of the downsides of using pure methanol was that the cooling in the combustion chamber on the intake stroke was so profound that it causes huge stress on the cylinder, valves and piston as they are repeatedly supercooled and then heated hundreds of times per second. Obviously you can try to avoid this problem by adding distilled water, but has anyone studied the long-term effects of this on an engine block?
I also think an injection system would be a total deal-breaker when it came time to sell the car; I've talked to a few co-workers about this, both tech-savvy and clueless, and they are universally freaked out by the idea of injecting water/alchohol mist into an engine during a boost cycle. A prospective buyer would see this as a sign that the car has been taken all the way to race car and probably driven to heck.
I'm not trying to be a buzzkill; I'm just curious why such a win/win mod is so rare, when it seems so logical. Would a CO2-sprayer for the intercooler have the same effect, without having to inject anything into the intake manifold?
Pardon my cynicism, but there HAS to be a downside to this, or it would come on a factory car stock -- even a Ferrari, Viper or Porsche. If a little $23k Japanese sports sedan can benefit from this, why don't the $100k exotics have it (or the American muscle cars?)
I think if you used water injection as a safety cushion to tune your car into an area where it would normally experience severe detonation, and then you had some type of failure in the water/alchohol injection system (air bubble, clogged injector, ran out of water) you'd experience an engine-threatening incident. Would the Subaru ECU be quick enough to go into "limp mode" before you cracked any pistons? What about gravity or momentum sloshing the water around in the tank under hard driving or track grades?
I was reading on one forum that one of the downsides of using pure methanol was that the cooling in the combustion chamber on the intake stroke was so profound that it causes huge stress on the cylinder, valves and piston as they are repeatedly supercooled and then heated hundreds of times per second. Obviously you can try to avoid this problem by adding distilled water, but has anyone studied the long-term effects of this on an engine block?
I also think an injection system would be a total deal-breaker when it came time to sell the car; I've talked to a few co-workers about this, both tech-savvy and clueless, and they are universally freaked out by the idea of injecting water/alchohol mist into an engine during a boost cycle. A prospective buyer would see this as a sign that the car has been taken all the way to race car and probably driven to heck.
I'm not trying to be a buzzkill; I'm just curious why such a win/win mod is so rare, when it seems so logical. Would a CO2-sprayer for the intercooler have the same effect, without having to inject anything into the intake manifold?
11-27-2005 | 09:55 AM
#11
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Posts: 15,494
From: Participating in some Anarchy!
Car Info: 2005 LGT wagon
A lot of questions and points to address.
Water/alcohol injection has been used for some time; it was standard equipment on most US & German fighters during WWII.
Again, Water/alcohol injection is not some magical elixir that will unleash the mad power.
Instead, think of it as running higher octane fuel only when you need it, and not having to run race fuel all the time.
That being said, if you run Water/alcohol injection, you will have to tune for it.
For example, after I installed the Water/alcohol injection system in my 05 STi, the dyno revealed that torque & power dropped, which was no surprise to me, as the AFRs were very rich.
To address the concern of supercooling the intake charge, my opinion is that it isn't a problem, as it isn't happening. The water mist doesn't cold shock the pistons as there isn't enough water present. Remember, small amounts of water are being injected in a superfine mist, and not just being poured into the combustion chamber.
Link to above info.
I don't use 100% alcohol as there is no increased benefit over a water/alcohol blend. And, as I've said before, water is cheaper than methanol.
You make some very excellent points.
As with any high performance modifications, come certain inherent risks and responsibilities.
For example, I only use distilled water to prevent mineral deposits.
I'm using a Spec C OEM tank & have incorporated the level indicator into the warning light on the cluster. Also, this tank helps to minimize any "dry spots" during driving.
Not to insult your co-workers, but their cars are already ingesting water in the form of water vapor...aka humidity.
Also, we're injecting water mist, not a continuous stream from a garden hose.
A CO2 halo would/could acclomplish the same thing, but less efficiently and with more cost.
I believe that one of the biggest reasons that water/alcohol injection is so rare is due to the opinionsbeliefs shared by your co-workers.
I understand your concern of water injection = driven hard, but doesn't a big FMIC suggest the same thing?
It's human nature to "fear" the unknown, but before poo pooing an idea, I like to do research.
A lot of research.
But then again, I'm a Mechanical Engineer by schooling, so it's in my DNA.
Water/alcohol injection has been used for some time; it was standard equipment on most US & German fighters during WWII.
Again, Water/alcohol injection is not some magical elixir that will unleash the mad power.
Instead, think of it as running higher octane fuel only when you need it, and not having to run race fuel all the time.
That being said, if you run Water/alcohol injection, you will have to tune for it.
For example, after I installed the Water/alcohol injection system in my 05 STi, the dyno revealed that torque & power dropped, which was no surprise to me, as the AFRs were very rich.
To address the concern of supercooling the intake charge, my opinion is that it isn't a problem, as it isn't happening. The water mist doesn't cold shock the pistons as there isn't enough water present. Remember, small amounts of water are being injected in a superfine mist, and not just being poured into the combustion chamber.
Originally Posted by The Manual for the Home and Farm Production of Alcohol Fuel
gasoline has a latent heat of about 140 Btu/lb; methanol, 474 Btu/lb; and ethanol, 361 Btu/lb. In an engine, vaporization of the gasoline fuel/air mixture results in a temperature drop of about 40 degrees Fahrenheit. Under similar conditions, the temperature drop for ethyl alcohol will be more than twice that of gasoline, and for methanol the drop will be over three times as great. These temperature drops result in a considerably greater "mass density" of the fuel entering the engine for alcohol as compared to gasoline. The result is a greatly increased efficiency for alcohol fuels. To visualize why, remember that at a given pressure, the amount of space a gas occupies is directly proportional to the temperature. For example, if one pound of a gas fits into a certain container at a given pressure and the temperature is cut in half, the container will now hold two pounds of the gas at the same pressure. In an engine, a stoichiometric mixture of methanol and air would be over three times colder than the same gasoline/air mixture. This means that there is now over three times (by weight) as much methanol in the cylinder. Now, even though methanol has only half the heat value of gasoline, the net gain in "volumetric mass efficiency" is over three times. So, for example, if the gasoline/air mixture in a given engine cylinder produces 100 Btu on each stroke, the same engine would produce 150 Btu per stroke with methanol. This power gain due to increased volumetric mass efficiency is the primary reason for the popularity of methyl alcohol as a racing fuel. With ethanol the effect isn't quite as dramatic, but the greater heat value partially offsets the lower latent heat. Overall, this power increase with alcohol fuels considerably mitigates the liability of low heat value.
However, the increased cooling due to latent heat sometimes creates a problem in an engine converted to run on alcohol. Once vaporized, a certain amount of heat is required to keep the fuel from condensing back to the liquid state before it reaches the cylinder. To accomplish this, an engine is designed to provide this heat to the intake manifold. Alcohol, because of its greater latent heat, requires more heat than gasoline. This is one of the reasons that racing engines have short path manifolds and multiple carburetors. The shorter the distance the fuel must travel to the cylinder, the less chance of condensation and fuel distribution problems. On a practical level, most engines that have been converted to alcohol supply enough heat once they are warmed up. The main problem, as with high performance racing engines, is in starting a cold engine. This problem and the related fuel distribution problem will be discussed later in more detail.
However, the increased cooling due to latent heat sometimes creates a problem in an engine converted to run on alcohol. Once vaporized, a certain amount of heat is required to keep the fuel from condensing back to the liquid state before it reaches the cylinder. To accomplish this, an engine is designed to provide this heat to the intake manifold. Alcohol, because of its greater latent heat, requires more heat than gasoline. This is one of the reasons that racing engines have short path manifolds and multiple carburetors. The shorter the distance the fuel must travel to the cylinder, the less chance of condensation and fuel distribution problems. On a practical level, most engines that have been converted to alcohol supply enough heat once they are warmed up. The main problem, as with high performance racing engines, is in starting a cold engine. This problem and the related fuel distribution problem will be discussed later in more detail.
I don't use 100% alcohol as there is no increased benefit over a water/alcohol blend. And, as I've said before, water is cheaper than methanol.
Originally Posted by meilers
I think if you used water injection as a safety cushion to tune your car into an area where it would normally experience severe detonation, and then you had some type of failure in the water/alchohol injection system (air bubble, clogged injector, ran out of water) you'd experience an engine-threatening incident. Would the Subaru ECU be quick enough to go into "limp mode" before you cracked any pistons? What about gravity or momentum sloshing the water around in the tank under hard driving or track grades?
I also think an injection system would be a total deal-breaker when it came time to sell the car; I've talked to a few co-workers about this, both tech-savvy and clueless, and they are universally freaked out by the idea of injecting water/alchohol mist into an engine during a boost cycle. A prospective buyer would see this as a sign that the car has been taken all the way to race car and probably driven to heck.
I'm not trying to be a buzzkill; I'm just curious why such a win/win mod is so rare, when it seems so logical. Would a CO2-sprayer for the intercooler have the same effect, without having to inject anything into the intake manifold?
I also think an injection system would be a total deal-breaker when it came time to sell the car; I've talked to a few co-workers about this, both tech-savvy and clueless, and they are universally freaked out by the idea of injecting water/alchohol mist into an engine during a boost cycle. A prospective buyer would see this as a sign that the car has been taken all the way to race car and probably driven to heck.
I'm not trying to be a buzzkill; I'm just curious why such a win/win mod is so rare, when it seems so logical. Would a CO2-sprayer for the intercooler have the same effect, without having to inject anything into the intake manifold?
As with any high performance modifications, come certain inherent risks and responsibilities.
For example, I only use distilled water to prevent mineral deposits.
I'm using a Spec C OEM tank & have incorporated the level indicator into the warning light on the cluster. Also, this tank helps to minimize any "dry spots" during driving.
Not to insult your co-workers, but their cars are already ingesting water in the form of water vapor...aka humidity.
Also, we're injecting water mist, not a continuous stream from a garden hose.
A CO2 halo would/could acclomplish the same thing, but less efficiently and with more cost.
I believe that one of the biggest reasons that water/alcohol injection is so rare is due to the opinionsbeliefs shared by your co-workers.
I understand your concern of water injection = driven hard, but doesn't a big FMIC suggest the same thing?
It's human nature to "fear" the unknown, but before poo pooing an idea, I like to do research.
A lot of research.
But then again, I'm a Mechanical Engineer by schooling, so it's in my DNA.
11-27-2005 | 03:19 PM
#12
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Joined: Mar 2003
Posts: 2,023
From: Phoenix, AZ
Car Info: Subaru Impreza WRX 2002
Thanks very much, Oaf; that's a thoughtful reply and even more sources for me to check out. I think that if you treat water/alchohol injection as a safety measure and not as a power-adding mod, then it begins to make much more sense.
11-29-2005 | 12:49 AM
#13
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Posts: 2,539
From: Farnborough, Hants
Car Info: the blue bucket
Interesting thread!
With the introduction of alky/water injection you will have to tune for it or the car will basically loose power through out (may even be undriveable). Depending on mods we have have seen some huge gains using these kits.
With regards to failsafes most popular kits have at the minimum low level indicators, we are working on a pressure sensor on the feed line that when sensing pressure drop reverts the wastegate solenoid to wastegate boost.
Mike
With the introduction of alky/water injection you will have to tune for it or the car will basically loose power through out (may even be undriveable). Depending on mods we have have seen some huge gains using these kits.
With regards to failsafes most popular kits have at the minimum low level indicators, we are working on a pressure sensor on the feed line that when sensing pressure drop reverts the wastegate solenoid to wastegate boost.
Mike
12-12-2005 | 06:44 AM
#15
Registered User
Joined: Nov 2003
Posts: 147
From: Lemoore, CA
Car Info: '03 Wrx w/vf-34, sti pinks,tbe, 2.5l cobb block
i agree with ilivas. but alky is a good cooling agent and will clean the inside of the intake track of all carbon build up. they do make kits that will let you know when you have a clogged injector and/or cut boost if the sensor reads an empty res.